Adsorption studies of Cu(II) onto biopolymer chitosan and its nanocomposite 5%bentonite/chitosan

2016 ◽  
Vol 73 (9) ◽  
pp. 2199-2210 ◽  
Author(s):  
Hamou Moussout ◽  
Hammou Ahlafi ◽  
Mustapha Aazza ◽  
Omar Zegaoui ◽  
Charaf El Akili

Chitosan (CS) and nanocomposite 5%bentonite/chitosan (5%Bt/CS) prepared from the natural biopolymer CS were tested to remove Cu(II) ions using a batch adsorption experiment at various temperatures (25, 35 and 45°C). X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis/differential thermal analysis (TGA/DTA) were used in CS and the nanocomposite characterisation. This confirmed the exfoliation of bentonite (Bt) to form the nanocomposite. The adsorption kinetics of copper on both solids was found to follow a pseudo-second-order law at each studied temperature. The Cu(II) adsorption capacity increased as the temperature increased from 25 to 45°C for nanocomposite adsorbent but slightly increased for CS. The data were confronted to the nonlinear Langmuir, Freundlich and Redlich–Peterson models. It was found that the experimental data fitted very well the Langmuir isotherm over the whole temperature and concentration ranges. The maximum monolayer adsorption capacity for the Cu(II) was 404–422 mg/g for CS and 282–337 mg/g for 5%Bt/CS at 25–45°C. The thermodynamic study showed that the adsorption process was spontaneous and endothermic. The complexation of Cu(II) with NH2 and C = O groups as active sites was found to be the main mechanism in the adsorption processes.

2019 ◽  
Vol 9 (2) ◽  
pp. 102-115
Author(s):  
Hanane Essebaai ◽  
Ilham Ismi ◽  
Ahmed Lebkiri ◽  
Said Marzak ◽  
El Housseine Rifi

Highly efficient low-cost adsorbent was applied for copper (II) ions uptake from aqueous solution. Characteristics of natural adsorbent were established using scanning X-ray diffraction (XRD), X-ray fluorescence, electron microscope (SEM) and Fourier Transform Infra-Red (FTIR). Various physicochemical parameters such as contact time, initial copper(II) ions concentration, adsorbent dosage, pH of copper (II) ions solution and temperature were investigated. The result showed that the adsorption of copper (II) ions by natural clay was favorable at pH=5,5. The adsorption was found to increase with increase in initial copper (II) ions concentration, and contact time. Equilibrium adsorption data were fitted using three isotherms and kinetic data tested with four kinetic models. Freundlich isotherm best described the adsorption of copper (II) ions onto utilised clay, the maximum monolayer adsorption capacity (qmax) was 8 mg/g. Pseudo-second-order model best described the kinetics of the adsorption process. Thermodynamic parameters such as Gibbs free energy, enthalpy and entropy were determined. It was found that copper (II) ions adsorption was spontaneous (ΔG°<0) and endothermic (ΔH°>0).


2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Mohamed S. Yahia ◽  
Ahmed S. Elzaref ◽  
Magdy B. Awad ◽  
Ahmed M. Tony ◽  
Ahmed S. Elfeky

Abstract Commercial Granulated Active Carbon (GAC) has been modified using 10 Gy dose Gamma irradiation (GAC10 Gy) for increasing its ability of air purification. Both, the raw and treated samples were applied for removing Chlorpyrifos pesticide (CPF) from ambient midair. Physicochemical properties of the two materials were characterized by Fourier Transform Infrared (FT-IR) and Raman spectroscopy. The phase formation and microstructure were monitored using X-ray Diffraction (XRD), Scanning Electron Microscopy (SEM), supported with Energy-Dispersive X-ray (EDX). The Surface area measurement was detected using BET particle size prosometry. Obtained outcomes showed that, the maximum adsorption capacity, given by Langmuir equations, was greatly increased from 172.712 to 272.480 mg/g for GAC and GAC10 Gy, respectively, with high selectivity. The overall removal efficiency of GAC10 Gy was notably comparable to that of the original GAC-sorbent. The present study indicated that, gamma irradiation could be a promising technique for treating GAC and turned it more active in eliminating the pesticides pollutants from surrounding air. The data of equilibrium has been analyzed by Langmuir and Freundlich models, that were considerably better suited for the investigated materials than other models. The process kinetics of CPF adsorbed onto both tested carbon versions were found to obey the pseudo first order at all concentrations with an exception at 70 mg/l using GAC, where, the spontaneous exothermic adsorption of Chlorpyrifos is a strong function for the pseudo-first order (PFO) and pseudo second order (PSO) kinetics.


Materials ◽  
2020 ◽  
Vol 13 (21) ◽  
pp. 5047
Author(s):  
Jun Cao ◽  
Peng Wang ◽  
Jie Shen ◽  
Qi Sun

Here, using Fe3O4@SiO2 as a precursor, a novel core-shell structure magnetic Cu2+ adsorbent (Fe3O4@zeolite NaA) was successfully prepared. Several methods, namely X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), Transmission electron microscope (TEM), Brunauer Emmett Teller (BET) and vibrating sample magnetometry (VSM) were used to characterize the adsorbent. A batch experiment was conducted to study the Cu2+ adsorption capacity of Fe3O4@zeolite NaA at different pH values, contact time, initial Cu2+ concentration and adsorbent does. It is found that the saturated adsorption capacity of Fe3O4@zeolite NaA on Cu2+ is 86.54 mg/g. The adsorption isotherm analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+ is more consistent with the Langmuir model, suggesting that it is a monolayer adsorption. Adsorption kinetics study found that the adsorption process of Fe3O4@zeolite NaA to Cu2+ follows the pseudo-second kinetics model, which means that the combination of Fe3O4@zeolite NaA and Cu2+ is the chemical chelating reaction. Thermodynamic analysis shows that the adsorption process of Fe3O4@zeolite NaA to Cu2+ is endothermic, with increasing entropy and spontaneous in nature. The above results show that Fe3O4@zeolite NaA is a promising Cu2+ adsorbent.


2015 ◽  
Vol 2015 ◽  
pp. 1-9
Author(s):  
Swarup Biswas ◽  
Umesh Mishra

Calcium pretreatedHevea brasiliensissawdust has been used as an effective and efficient adsorbent for the removal of copper ion from the contaminated water. Batch experiment was conducted to check the effect of pH, initial concentration, contact time, and adsorbent dose. The results conclude that adsorption capacity of adsorbent was influenced by operating parameters. Maximum adsorption capacity found from the batch adsorption process was 37.74 mg/g at pH of 5.6. Various isotherm models like Langmuir, Freundlich, and Temkin were used to compare the theoretical and experimental data, whereas the pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were applied to study the kinetics of the batch adsorption process. Dynamic studies were also conducted in packed-bed column using different bed depths and the maximum adsorption capacity of 34.29 was achieved. Characterizations of the adsorbent were done by Fourier transform infrared spectroscopy, scanning electron microscope, and energy dispersive X-ray spectroscopy.


2019 ◽  
Vol 79 (11) ◽  
pp. 2106-2115 ◽  
Author(s):  
Fengfeng Ma ◽  
Baowei Zhao ◽  
Jingru Diao

Abstract A magnetic cotton stalk biochar (MCSBC) was synthesized through chemical co-precipitation, based on cotton stalk biochar (CSBC). The MCSBC and CSBC were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and vibrating sample magnetometry. The characterization analyses showed that the magnetization process endowed the CSBC with excellent magnetic properties with a superparamagnetic magnetization of 27.59 emu/g. Batch adsorption experiment results indicated that the Cr(VI) maximum adsorption capacity of MCSBC was 20.05 mg/g, which was higher than that of CSBC (18.77 mg/g). The adsorption kinetic data were well fitted by the pseudo-second-order model and the adsorption isotherms were well represented by the Sips isotherm model. The thermodynamic studies indicated that the adsorption process was spontaneous and endothermic, and the entropy increased. The potential adsorption mechanism was the electrostatic adsorption of anionic Cr(VI) to the positively charged MCSBC surface, the reduction of Cr(VI) into Cr(III) and the complexation of Cr(III) by oxygen-containing functional groups of MCSBC. The regeneration studies showed that MCSBC kept 80% of its initial Cr(VI) adsorption capacity in the cycle. All the findings suggest that this novel magnetic biochar could be used in the field of Cr(VI)-containing wastewater treatment.


2019 ◽  
Vol 79 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Meixia Zheng ◽  
Fengli Lian ◽  
Yujing Zhu ◽  
Bo Liu ◽  
Zheng Chen ◽  
...  

Abstract Modified xanthan gum (XG-AM-TTE) was employed as an adsorbent to study the adsorption behavior, thermodynamics and kinetics of crystal violet (CV) from an aqueous solution. Fourier transform infrared spectroscopy analysis indicates that the functional groups present in the adsorbent, such as carboxyl, ester and hydroxyl groups, are included on the external surface of the material, and these groups are potential active sites for interaction with CV. According to X-ray diffraction results, the structure of XG-AM-TTE after CV adsorption became more disordered, and the microstructure change is an indication of effective adsorption of CV to the surface, with CV becoming remarkably dispersed in the adsorbent according to the scanning electron microscopy observations. The adsorption kinetics and adsorption equilibrium were best described by the pseudo-second-order model and Freundlich isotherms, respectively. The thermodynamic parameters, as the Gibbs-free energy (ΔG), enthalpy (ΔH) and entropy (ΔS), indicated that the adsorption is a spontaneous, endothermic and entropy increase process. The maximum adsorption capacity of XG-AM-TTE was 183 ± 12 mg/g, suggesting that XG-AM-TTE is an efficient adsorbent.


2013 ◽  
Vol 29 ◽  
pp. 34-43
Author(s):  
Puspa Lal Homagai

Cellulose, hemicelluloses and lignin are the main constituents found in sugarcane (Saccharum officinarum) bagasse having many surface active sites containing hydroxyl and/or phenolic groups which are effective for chemical modification. The biowaste was first charred with concentrated sulphuric acid and then the charred aminated sugarcane bagasse (CASB) was prepared by reduction followed by oxidation. The developed bio-sorbent was characterized by SEM, TGA/DTA, FTIR and elemental analysis. Batch adsorption methods were carried out to determine Pb+2 sorption capacities at different pH ranges and sorbate concentrations. The maximum adsorption capacity for Pb+2 was found to be 323 mg g-1 with an efficiency of 98% at pH 4.The experimental data showed a good fit to Langmuir isotherm as compared to Freundlich isotherm models. The kinetics was best fitted with the pseudo-second order model. The adsorption equilibrium was attained within 20 min. The high adsorption capacity and fast kinetics results of the charred aminated sugarcane bagasse indicated that it might be potential adsorbent for the removal of lead from contaminated water. DOI: http://dx.doi.org/10.3126/jncs.v29i0.9235Journal of Nepal Chemical SocietyVol. 29, 2012Page: 34-43Uploaded date : 12/3/2013


2016 ◽  
Vol 6 (4) ◽  
pp. 562-573 ◽  
Author(s):  
Farshad Omidvar-Hosseini ◽  
Farid Moeinpour

Acacia Nilotica seed shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles were synthesized by a low-cost, simple, and environmentally benign procedure. The adsorbent was characterized by several methods including X-ray diffraction, scanning electron microscopy and Fourier transform infrared spectroscopy. Then, the potential of Acacia Nilotica seed shell ash supported Ni0.5Zn0.5Fe2O4 magnetic nanoparticles was investigated for adsorption of Pb(II). The effect of different parameters including contact time, pH, adsorbent dosage and initial Pb(II) concentration on the Pb(II) removal yield was studied. The experimental data were fitted well with the pseudo-second order kinetic model (R2 = 0.999). The adsorption isotherm was described well by the Langmuir isotherm (R2 = 0.900) with a maximum monolayer adsorption capacity of 37.6 mg g–1. The process for purifying water treatment presented here is easy using the magnetic nanoparticles. Therefore, this adsorbent was found to be useful and valuable for controlling water pollution due to Pb(II) ions.


Catalysts ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1137
Author(s):  
Roberto Machado Garcia ◽  
Robert Carleer ◽  
Maria Arada Pérez ◽  
Jeamichel Puente Torres ◽  
Ying Gu ◽  
...  

Fe-TiO2/AC and Co-TiO2/AC composites were prepared from activated carbon (AC) derived from residues of peanut hulls and TiO2 photocatalyst, electrochemically prepared from titanium scrap, and doped with Fe and Co, respectively. The adsorption capacity and photocatalytic activity of the Fe-TiO2/AC and Co-TiO2/AC composites were studied for removing and degrading Cibacron Yellow F-4G (CYF-4G) from wastewater. Doped ACs were characterized by thermogravimetry (TGA), scanning electron microscopy (SEM), X-ray diffraction (XRD), a new X-ray absorption technique (XRA), and elemental analysis (EA). Interesting relationships were found between SEM, XRA, and TGA data and the doped amount of catalyst on ACs. Optimal dye adsorption was found at a pH of 2.0. The CYF-4G adsorption kinetics are followed according to the pseudo-second order model. The experimental data revealed that the Langmuir model fits better than the Freundlich and Temkin models. A decrease in adsorption capacity was observed when the catalyst dope percentage increased. A removal and degradation efficiency of the dye close to 100% was achieved around 120 min. A synergistic adsorption and photocatalytic degradation effect of the Fe-TiO2/AC and Co-TiO2/AC composites could be observed when adsorption experiments were conducted under simulated visible radiation.


2014 ◽  
Vol 70 (12) ◽  
pp. 2047-2055 ◽  
Author(s):  
Shashikant Kahu ◽  
D. Saravanan ◽  
Ravin Jugade

A sulfate-crosslinked chitosan (SCC) was prepared for effective detoxification of hexavalent chromium (Cr(VI)) from effluents. SCC was characterized using Fourier transform infrared, X-ray diffraction, scanning electron microscopy and energy dispersive X-ray studies. The maximum adsorption of Cr(VI) was observed at pH 6.0 with adsorption capacity of 157 mg/g in accordance with the Langmuir adsorption isotherm model. The adsorption process was found to follow the pseudo-second-order rate kinetics. From the study of various thermodynamic parameters (Gibbs energy, entropy and enthalpy changes), the adsorption capacity was found to decrease with increase in temperature. Column studies were carried out to obtain a breakthrough point of the adsorbent. The adsorbent was regenerated using sodium hydroxide with no change in the adsorption efficiency for up to 10 cycles. Effect of diverse ions on adsorption efficiency was studied and SCC was applied for Cr(VI) removal in synthetic effluents.


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